OSAC Lexicon
The OSAC Lexicon is a compendium of forensic science terms and definitions. This terminology tool was created to help bring consistency and understanding to the way terms are used by the various forensic science. Use of the OSAC Lexicon does not replace the need to reference the original published source.
The terms and definitions in the OSAC Lexicon come from the published literature, including documentary standards and technical reports. It is continually updated with the latest work from OSAC units, as well as terms from newly published documentary standards and standards elevated to the OSAC Registry.
Gradually terms are evaluated and harmonized by the OSAC to a single term. This process results in an OSAC Preferred Term. An OSAC Preferred Term is a term, along with its definition, that has undergone review and evaluation by the FSSB Terminology Task Group and has been approved by the FSSB. The FSSB recommends that subcommittees use OSAC Preferred Terms when drafting standards.
The OSAC Lexicon should be the primary resource for terminology and used when drafting and editing forensic science standards and other OSAC work products.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
a difference in one or more characteristics between compared items that is sufficient to determine that the compared items did not originate from the same source, are not the same source, or do not share the same composition or classification.
Discussion—What is sufficient depends on the performance and limitations of the method used on the material in question.
a difference in a feature or property between compared items that is substantial enough to determine that they did not originate from the same source.
An item of known origin used in footwear and tire examinations.
The friction ridge prints of an individual, associated with a known or claimed identity,and deliberately recorded electronically, by ink, or by another medium (also called 'known prints').
A specimen of physical evidence of known origin
Quantity defining an interval about a result of a measurement that may be expected to encompass a large fraction of the distribution of values that could reasonably be attributed to the measurand
Quantity defining an interval about a result of a measurement that may be expected to encompass a large fraction of the distribution of values that could reasonably be attributed to the measurand. DISCUSSION(1) The fraction may be regarded as the coverage probability or level of confidence of the interval. (2) To associate a specific level of confidence with the interval defined by the expanded uncertainty requires explicit or implicit assumptions regarding the probability distribution characterized by the measurement result and its combined standard uncertainty. The level of confidence that may be attributed to this interval can be known only to the extent to which such assumptions can be justified. (3) An expanded uncertainty U is calculated from a combined standard uncertainty uc and coverage factor k using: U =k X uc.
Anyone testing any idea has a strong expectation that leads to an influence about the outcome.
A person displaying special skill and knowledge in a given area derived from training, education, or experience.
The testimony made by a qualified person about a scientific, technical, or professional issue. An expert is often called upon to testify due to his/her familiarity with the subject or special training in the field.
A coherent, scientifically sound statement or statements regarding the meaning of analytical findings in a forensic case that is formulated from a consideration of the synthesis of analytical data, pre-analytical factors, case history, and other relevant information
A bloodstain pattern resultsing from blood forced by airflow out of the nose, mouth, or a wound.
Variations in appearance that can be attributed to factors such as distortion, movement and pressure. These differences do not result in an exclusion decision.
A material with a pressure ratio (maximum pressure/pressure at ignition, in absolute units) equal to or greater than 2.0 in any test when tested using the explosibility or Go/No-Go screening test described in Section 13 of ASTM E1226, Standard Test Method for Explosibility of Dust Clouds. [68, 2018]
the sudden conversion of potential energy (chemical or mechanical) into kinetic energy with the production and release of gases under pressure, or the release of gas under pressure; these high-pressure gases then do mechanical work such as moving, changing, or shattering nearby materials.
The sudden conversion of potential energy (chemical or mechanical) into kinetic energy with the production and release of gases under pressure, or the release of gas under pressure. These high-pressure gases then do mechanical work such as moving, changing, or shattering nearby materials.
Study of how chemistry, physics, fire science, engineering disciplines of fluid and solid mechanics, and heat transfer interact to influence explosion behavior.
Study of how chemistry, physics, fire science, engineering disciplines of fluid and solid mechanics, and heat transfer interact to influence explosion behavior.
Any chemical compound, mixture, or device that functions by explosion.
A single substance, or a mixture of substances, that is capable of producing an explosion upon initiation (see high explosives and low explosives). explosive compound, na single chemical compound that can produce an explosion. explosive mixture, na mixture of separate fuel and oxidizer components that together can produce an explosion.
a single chemical compound that can produce an explosion.
Any material that can act as fuel for an explosion.
a mixture of separate fuel and oxidizer components that together can produce an explosion.
the detection, identification, on-site evaluation, rendering safe, recovery, and final disposal of unexploded explosive ordnance; it may also include explosive ordnance which has become hazardous by damage or deterioration.
A chemical substance that can be utilized in the production of explosives by either mixing or blending with other substances, or by chemical processing. The vast majority of chemicals are used for legitimate purposes. However, some chemicals could potentially be misused for the illicit manufacture of homemade or improvised explosive. Indeed, relatively small amounts of select chemicals can be applied in certain processes that produce a significant amount of explosives.
Material remaining from an explosive deflagration or detonation or from direct contact with an explosive. Explosive residue generally does not have a discernible morphology; can be visible or non-visible; and can contain uninitiated and post-combustion components.
material remaining from an explosive deagration or detonation or from direct contact withan explosive. Explosive residue generally does not have adiscernible morphology, can be visible or non-visible, and cancontain uninitiated and post-combustion components.3.2.1.1 DiscussionVisible explosive residue can be pres-ent in large (grams) and small (single particle or single crystal)quantities.
an arrangement of explosive components by which the initial force from the primer is transmitted and intensified until it reaches and detonates the main explosive composition.
A canine trained to detect and alert to the presence of explosives and explosives related substances (e.g., propellants, oxidizers, precursors) for which it has been trained that may be located in the environment.
A canine trained to detect and alert to the presence of explosives and explosives related substances (e.g., propellants, oxidizers, precursors) for which it has been trained that may be located in the environment and/or person borne.
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The side of a structural assembly or object that is directly exposed to the fire.
The parameter, associated with the assessment method used, that characterizes the dispersion of the values that could reasonably be attributed to the measurand.
File system typically used with Linux-based operating systems
An evaluation of practitioner performance against pre-established criteria by means of interlaboratory comparisons. [ISO/IEC 17043:2010]
the condition in which a birefringent particle appears dark when viewed between crossed polarizers.
The condition in which a birefringent particle appears dark when viewed between crossed polarizers
A procedure where the reinforcement of a previously reinforced behavior is discontinued with the intention to reduce the occurrence of that behavior
To cause to cease burning.